air leak

[moose]

Hello all
after searching on my 1970 mci
i found a major air leak
the air cylinder that tightens up the blower box squirrel fans is leaking air when i shut the bus down .
i beleive it is leaking when the bus is running
is this normal or should ther be 0 air leakage

thank you
trevor

[TomC]

On ANY air pressure operated item, no air leakage.  My guess there is an O ring rebuild kit available.  Good Luck, TomC

[moose]

hello
I live in Calgary
i have looked around and the bus repair people say buy a new cylinder
looks that is what i will do
thanks trevor

[zubzub]

if you have the time and are going to repalce it anyway, why not take it apart and see if you can rebuild it.   a decent bearing supply house may have the o rings you need.

[bevans6]

On mine, there is a valve handle that you can turn to dump air when you want to release the cylinder pressure to allow you to change or remove the belt easily.  On my bus that valve leaks quite badly when the air pressure is low, but stops leaking when the bus is up to normal pressure.  Then there is a pressure regulator that should be set to 21 psi, and a schrader valve to allow you to test the pressure setting.  And then of course the cylinder itself.  You don't want full air pressure going to that cylinder, you definitely want the regulator to be there and working.

Brian

[JackConrad]

Another option I have seen used is to replace the air cylinder with a turnbuckle. I think he used a turnbuckle that had 1/2" threaded eye bolts.  Jack

[wildbob24]

I'll second the turnbuckle suggestion. If you do that, you can remove the cylinder, regulator and valve and the related plumbing and eliminate at least 3 potential leaks. Well worth doing.

Bob

[moose]

hello to all whom responded
Thank you
I do like the idea of a turnbuckle
would there be any consequences if i put a turnbuckle in place of cylinder
how tight should the belt be
thank you trevor

[JackConrad]

   I have not heard of any negative results of using a turnbuckle.  It should be tight enough to prevent the belt from "flopping" or slipping.  
  I would air up the bus to full pressure and feel the belt tension, then adjust the belt to a similar tension after installing the turnbuckle. Tension can be measured if you have a small fish scale. OEM cylinder was set at 35 PSI air pressure, but I do not know how much pressure was exerted on the belt through the bell crank that is attached to the air cylinder.  Jack

[Chopper Scott]

I rebuilt the air cylinder that tightened up the generator with common o rings from a local part store. If I remember right they were more of a flat square ring. Can't say anything about longevity as I have since scrapped the gen in favor of an alternator and went with a turnbuckle.

[Busted Knuckle]

Turnbuckles are an excellent option for busnuts!
Kinda a hassle for revenue coaches though! If it has proper working cylinders a driver can change the belt with getting dirty and no tools! (put the turnbuckle on and you can forget about most drivers attempting to change it! I know we have been there done that! )
  BK